Park
Batter
Runs for the parks he batted in: a credit in pitchers’ parks, a debit in hitters’ parks.
Pitcher
Runs for the parks he pitched in, from home runs: a credit in hitters’ parks.
Formula
Hitters: the total over his plate appearances of (1 − that park’s run factor) × league runs per plate appearance. Pitchers: 13 / 9 × the total over batters faced of (that park’s home run factor − 1) × league home runs per plate appearance.
Our own model
Not checked against Savant. A season is written only when every check on the aWAR page passes.
Notes
A club’s factor is its rate at home over its rate on the road, pooled over up to three seasons in one ballpark and pulled toward 1. Pitchers are adjusted for home runs only, the one part of ifFIP a park moves.
Era caveats
aWAR begins in 2016
Savant’s fielding leaderboard begins in 2016, so 2015 has no aWAR and no part of it.